William Lipscomb

April 18, 2011

When I was a graduate student, there was a cartoon posted on one of the chemistry bulletin boards. It was entitled, "A Boron Chemist's Version of the Periodic Table." It was a Periodic Table, but it was drawn so that the boron square filled as much area as the rest of the table. As a putative metallurgist, I didn't see what was that interesting about boron, except for the fact that the chemistry building was once evacuated because of a leaky boron trifluoride BF3 gas cylinder. All the action seemed to be at carbon, boron's next door neighbor. William Nunn Lipscomb, an important figure in boron chemistry, died on April 14, 2011, at age 91.[1-4]

What is most interesting to me is that Lipscomb almost became a physicist. He spent one year studying physics at Caltech before switching to physical chemistry. Lipscomb was awarded a Ph. D. in Chemistry from Caltech in 1946. He then taught at the University of Minnesota for an extended period through 1959, when he became a professor of chemistry at Harvard University. At Harvard, he was Abbott and James Lawrence Professor of Chemistry from 1971 to 1990, and Abbott and James Lawrence Professor of Chemistry Emeritus from 1990.[1]

Linus Pauling was Lipscomb's thesis advisor at Caltech, and Pauling's ideas influenced him as they did most chemists. Lipscomb, however, thought that Pauling's ideas about boron bonding were wrong. One problem in determining the chemistry of boron was that very few boron compounds existed; and the ones that did, such as boron trifluoride (BF3) that I mentioned earlier, had the expected bonding.

The subsequent low temperature studies of single crystals of these volatile and unstable boranes were not without hazards. Vacuum line techniques were learned as we needed them. Fortunately, no serious injuries were incurred as a result of several explosions resulting from cracks in these vacuum systems. I was relieved, on one occasion, when I had taken Russell Grimes to a hospital in Cambridge after one of these explosions to hear the doctor tell me, "Louis Fieser sends me much more interesting cases than you do."

Fieser was a Harvard organic chemist who was involved with a wartime project to have bats with timed incendiary charges start fires in Japan.

During World War II, Lipscomb did military research during the day and his graduate research at night. Lipscomb's doctoral dissertation was locked in a safe for several years because it contained classified research.[2]

In order to elucidate the bonding structures of the boranes, Lipscomb and his students would crystallize them at low temperature and perform X-ray crystallographic analysis. One early, and quite unusual discovery, was that the boron atoms in some boranes were bonded together by a hydrogen atom. Until that time, bonds were considered to be possible only when atoms shared an electron pair. His seminal paper, "The Valence Structure of the Boron Hydrides," coauthored with Bryce Crawford Jr. and W. H. Eberhardt, appeared in 1954.[6] Even Pauling was impressed.[7]

Drawing of the structure of B4H10 from William Lipscomb's Nobel Prize lecture.

Lipscomb was awarded the 1976 Nobel Prize in Chemistry for "his studies on the structure of boranes illuminating problems of chemical bonding." Two of Lipscomb's students were also awarded chemistry Nobels; namely, Roald Hoffmann (1981) and Thomas Steitz (2009).

One interesting item, as revealed in an interview with Lipscomb in 2001, is that he lost NSF funding shortly after receiving the Nobel Prize because the NSF thought that boranes were a dead field.[8] This forced him to change his research field to biochemistry, where he worked on the structure determination of proteins using the crystallographic techniques that had served him well for the boranes.